The trailer was release alongside some artwork which apart from the Doctor and Clara also shows a Cyberman’s head and the Steven Moffatt’s The Silence. In the trailer some Daleks also appear.

It is thought that this episode will deal with the number of regenerations that Doctor can have. Up until now it has been thought that Timelords can only have 13 regenerations. In the Tom Baker story “The Deadly Assassin“, back in the 1970’s, it was said that that Time Lords can regenerate twelve times before dying (thirteen incarnations in all).

William Hartnell,

Patrick Troughton,

Jon Pertwee

Tom Baker

Peter Davison

Colin Baker

Sylvestor McCoy

Paul McGann

John Hurt

Christopher Eccelston

David Tennant

David Tennant (version 2?)

Matt Smith

Where this leaves Peter Capaldi and future of the show we may find out?